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Porpoises are distinguished from dolphins by their flattened, spade-shaped teeth distinct from the conical teeth of dolphins, and lack of a pronounced beak, although some dolphins (e.g. Hector's dolphin) also lack a pronounced beak. Porpoises, and other cetaceans, belong to the clade Cetartiodactyla with even-toed ungulates.
The family Balaenidae, the right whales, contains two genera and four species. All right whales have no ventral grooves; a distinctive head shape with a strongly arched, narrow rostrum, bowed lower jaw; lower lips that enfold the sides and front of the rostrum; and long, narrow, elastic baleen plates (up to nine times longer than wide) with fine baleen fringes.
Cetacea (/ s ɪ ˈ t eɪ ʃ ə /; from Latin cetus ' whale ', from Ancient Greek κῆτος () ' huge fish, sea monster ') [3] is an infraorder of aquatic mammals belonging to the order Artiodactyla that includes whales, dolphins and porpoises.
Dolphins and porpoises are hunted in an activity known as dolphin drive hunting. This is done by driving a pod together with boats and usually into a bay or onto a beach. Their escape is prevented by closing off the route to the ocean with other boats or nets.
However, at higher speeds dolphins and porpoises will seek out the pressure wave and its maximum energy zone in order to ride the wave by holding their flukes in a fixed plane, with only minor adjustments for repositioning. [19] Wave-riding reduces the energetic cost of swimming to the dolphin, even when compared to slower swimming speeds. [19]
A humpback whale (Megaptera novaeangliae) A leopard seal (Hydrurga leptonyx). Marine mammals are mammals that rely on marine (saltwater) ecosystems for their existence. They include animals such as cetaceans (whales, dolphins and porpoises), pinnipeds (seals, sea lions and walruses), sirenians (manatees and dugongs), sea otters and polar bears.
Dall's porpoises are opportunistic, hunting a variety of surface and mid-water species. Common prey are mesopelagic fish, such as myctophids , and gonatid squid. [ 2 ] [ 6 ] [ 11 ] Stomach content analyses have also found cases of crustacean consumption, including krill and shrimp, but this is abnormal and likely not an important part of their ...
The Yangtze finless porpoise (Neophocaena asiaeorientalis) is a species of toothed whale in the family Phocoenidae, the porpoise family.It is endemic to the Yangtze River in China, making it the country's only known freshwater cetacean following the possible extinction of the baiji (Lipotes vexillifer), a freshwater dolphin also native to the Yangtze. [3]